1. Field of the Invention
This invention relates generally to novel N,N'-bis(alkyl salicylidene)ethylene or phenylene diamines and the transition metal complexes thereof, particularly Cu, Mn and Fe and the use of the complexes as an additive to diesel fuels.
2. Description of the Related Art
The use of various metal compounds, particularly transition metal compounds such as compounds of manganese, lead, copper, zinc, cobalt and nickel, to name a few, in fuels to reduce soot formation and improve combustion properties of the fuel is known. U.S. Pat. No. 4,673,412 teaches an oil-soluble, transition metal complex of a Mannich base and an oxime wherein the molar ratio of I:II is from about 1:10 to about 10:1 are useful in association with diesel fuels or fuel oils which give good storage stability and at the same time effectively reduce the ignition temperatures for soot particulates. The transition metal complexes of the N,N'-bis(alkylsalicylidene)ethylene or phenylene diamines according to the present invention are useful as additives in diesel fuel to reduce soot formation in diesel exhaust in the absence of mannich bases.